Heat transfer method to preclude ice formation on paving



July 20, 1965 J. R. TIPPMANN HEAT TRANSFER Mmfrnon fro PREGLUDE 1cm FORMATION on PAVING Filed nec. 19, 1961 Anz TEMP. o F.

SLAB TEM?. ABQNE 37.2 3G

2 Sheets-Sheet 1 F QOST LEVEL.

FLmD TE-M1: Annex., 459

INVENTOR. JOSEPH l2. hpDMANN o July 20, 1955 J. R. TIPPMANN 3,195,619

HEAT TRANSFER METHOD TO PRECLUDE ICE FORMATION 0N PAVING Filed Deo. 19, 1961 2 Sheets-Sheet 2- loo 'f INVENTOR.

'2' JosEm-x E.T\DPMANN Klon.. BY

ATTORNEYS United States Patent 3,195,619 FEAT TRANSFER METHD T@ PRECUUE ESE Ft'llll'irllbl N PAY/lirici i .loscplr Robert Tippmann, Fort Wayne, lud., assigner or one-half to John Edv-'md Baker, Washington, UC. Filed Dec. 19, 196i, tier. No. 11669539 2 Claims. (til. 165-1) This invention pertains to apparatus used in a system of heat transfer, and more specifically, to a method effective to maintain paved areas such as driveways, streets, aircraft runways, highways, and the like at a temperature to preclude the formation of ice thereon.

lt is a primary object of this invention to provide a system ofthe character specied above which, after installation, functions through the utilization of the diierences in temperature as they occur in nature and does not involve operating expense. Recognizing the safety and convenience arising from maintaining paved areas of the type mentioned above in ice free condition throughout the year in climates wherein freezing weather occurs, the prior art has developed various means for attaining this object, such previously known systems involving, for the most part, electrical resistance elements embedded in the pavement, or iiuid transmission lines therein connected with an outside pumping source. Each of said previous means is effective for the purpose, but each involves substantial operating expenditures. he present invention utilizes the natural heat of the earth below frost level as its energy source, and once installed, is completely without operating expense.

lt is therefore an object of this invention to supply a heat transfer device eliective to transmit heat to pavement located on or adjacent ground level from the natural heat contained within the subterranean earth therebelow.

Another object oi this invention resides in the provision of a non-coniplex method which employs a liquid medium which is convertible into a gaseous state upon application of heat thereto and back to the liquid state upon application of cold thereto and absorbed by the medium in the liquid state in the above described environment.

An ancillary object is the provision, in a method of the character described, of dispersion o the heat transfer media.

Other and further objects and advantages of this invention will become apparent from a consideration of the following specification when read in conjunction with the annexed drawings, in which:

FIGURE 1 is a perspective view, partly broken away= ot a pavement strip embodying the meto-od and apparatus of heat transfer of the present invention;

FIGURE 2 is an enlarged side elevational view of an element of the apparatus in its subterranean location, partly in section;

FlGURE 3 is a further enlarged, foreshortened, vertical section thereof;

FIGURE 4 is a view similar to FIGURE l, modification;

FIGURE 5 is an enlarged top view showing the modified form of FlGURE 4, the pavement being in section; FGURE 6 is a fragmentary elevation thereof; and

FGURE 7 is a further enlarged cross-section, taken substantially `along section line '7 7 of FEGURE 6, lool.- ing in the direction of the arrows.

Proceeding to a description of the invention, in Fl"- URES 1 through 3, the involved apparatus is shown as comprising an elongated vessel or tube itil of generally inverted L-shape formed, in the main, of tubular metal preierably of a type substantially impervious to corrosion when installed in the ground, and when exposed to the interior vaporization and condensation of a volatile showing a substance such as ammonia. The vessel lo includes a normally opstanding lirst tubular portion l2 having an upper end portion le terminating in an open end Ito, and an opposite lower end portion l winch terminates in an open end Ztl. As seen in FIGURE 3, a pointed closure plug 2.2 seals the open end 2), plug 22 including a reduced neck 2d which is received in the said open end Ztl and permanently seals the same. The pointed tip $26 of plug 22 serves as an aid in forcing the vessel into the ground. The i'irst tubular portion l2 comprises a vaporiration chamber when'in use, as will appear below.

integrally connected to the open upper end lo of the vessel l@ is a second tubular element 23. The element 2? includes an open proximal end 5@ secured to the open end lo of the rst element l2 at a shoulder portion 3l. so that the elements l2 and 2S are in open communication with one another. The element 23 has an open outer end 32, which, during fabrication of the apparatus, is permanently sealed by a plug 34. Element 23 forms a condensation chamber.

Prior to sealing of the ends of the vessel ll?, it is supplied with a measured quantity of a liquid medium selected from the group consisting of ammonia, Freon (dichlorodiliuoromethane), or other refrigerants ln the selection or" the medium, it is only necessary that it possess the property of being convertible to a liquid state at low temperature and back to a gaseous state at a higher temperature or substantially 45 F., and condense back to its liquid state at a temperature lower than the gasiying or vaporizing temperature or slightly above 32 F. Exe ilary temperatures are shown in FIGURE 3 ot the drawing. The aforementioned substances meet this requirement as do other volatile liquids known in the art, The measured quantity of the substance to be utilized must be auch that, with a portion oi' the substance in its liquid state and the remainder in its gaseous state, the vessel l@ will be substantially iilled, as appears in more detail below.

The environment selected for illustration herein cornpriscs a slab 3b of concrete or the like disposed on or adjacent the ground level. Element 2? has been permaneatly embedded in the slab 3 in a generally horizontal but sliehtly inclined position, and element l2 is vertically disposed in tue ground beneath tne slab. ln FGURE 3, a typical situation is shown, the opstanding portion l2 being inserted in the ground a suilicient distance such that a substantial portion thereof is disposed beneath the frost line wherein the temperature remains fairly constant at approximately 55 F. Heat from the ground has been transferred to the volatile substance within the lower end por .ion i8 of the element l2, raising its temperature to vaporization level. Since the air temperature about the slab is quite cold (8 E), the slab is o a lower temperature than the vapor and this results in condensation of the vapor as it reaches the horizontal element The selected inclination of the element from tl e horizontal results in a drainage of condensed liquid back into the element l2.. Heat carried by the vapor has been found sur'licient to maintain the slab Se above 32 F., and to thereby eicctiveiy prevent freezing thereon.

lt will be seen that a constant cycle oi operatic-n is involved so long as the temperature oi the ambient atmosphere remains less than that of the ground below frost level.

lt will be obvious to those skilled in the art that the dimensions or" the vessel lil will necessarily be varied in accordance with temperatures liltely to be encountered in various areas, and that the depth of the lower end portion i3 must be increased in areas of extreme cold by comparison with the death which would be eiective in more temperate climates.

In FIGURES 4 through 7, an alternative structure is shown, like elements in the drawings carrying the same reference characters as in the Iirst described formwith the letter a appended thereto, In the last-named iigures, the horizontal portion ZS is replaced by a manifold dispersion system 28u.

Manifold system 23a comprises essentially a rneans for wider dispersion of the gaseous form of the volatile substance. In the various figures, it will be noted that the dispersion system 28a includes a lateral tube 10@ having Voppositely inclined portions 102 and 164 disposed at each side of the upright element rZa and terminating at its outer ends and forwardly disposed portions 11.06, 108, each sealed by plugs 34a. The portions 166 and 10S are Yinclined in the direction of the element i251 so that run-back may occur. Further included in the dispersion means .25a is a central element Ulti interposed between the portions like and 10S and similarly inclined.

Gperation of the form of the invention shown in FIG- URES 4 through 7is substantially as'hereinbefore described with reference to the form of the invention in FIGURES 1 through 3. ln theformer case as in the latter, the vessel Title is filled with a measured quantity of the volatile substance, and the dispersion means 23a is embedded in the slab 36a. in each form of the invention, the dispersion means 2S or 28a of the transfer system are adapted for arrangement in a network in the slab for eifectiveheat transfer, the network arrangement being selected for the maximum effectiveness of the heat dispersion'.

The foregoing are intendedV as illustrative examples of the invention'and of its manner of utilization, and the scope of this invention is to be limited only by the appended claims.

lVhat is claimed is:

1. The method of maintaining a ground surface covered by a slab of paving at a temperature to preclude the formation of ice thereon which comprises positioning a plurality of closed elongated members in a horizontally spaced ,.relationship, each having a portion extending in anteriore an upright direction below said surface with the upper end adjacent to and spaced below, the paving, positioning substantially horizontal condensation chambers in embedded relation in the paving in a network, with the condensation chambers each being attached to one of said upright-extending portions Vto complete the closed elongated member, each of said members being partially iilled with a medium in a liquid state and convertible into a gaseous state upon imposition of heat in the range of at least substantially 45 F. thereto and convertible from the gaseous state `to the liquid state upon imposition of cold in the range of at least substantially 32 F., thereto,` the lower end portions of said members being submerged below said surface to an extent such as to lie below the frost line of the subterranean earth, the liquid medium in the lower end portions of said members being subjected to the heat of adjacent regions of the subterranean earth to thereby gasify some of said medium and cause the Vmedium converted to the gaseous state to be evolved from the liquid medium and ow into the condensation chambers of said'members, the medium in the gaseous state when in the condensation chambers' of said members being'subjected to the cold of the adjacent paving to thereby condense the medium in the gaseous state and' be returned to and absorbed in the respective liquid mediums to heat the paving tothe temperature to kpreclude formation of ice.

,2. The method according to claim 1l, wherein said medium is ammonia.

References Cited by the Examiner n UNrrnD srATns PATENTS Y 2,499,736 3/50 Kleen 62- 119 2,645,209 7/53 Digby v 16S- 105 XR 2,738,927 3/56 Birkemeier 237-69 2,835,480 5/58 Perez 165-105 2,937,009 5/60 Anderson 165--45 XR ClrlARLESY SUKALO, Primary Examiner. JOHN I. CAMBY, Examiner. 

1. THE METHOD OF MAINTAINING A GROUND SURFACE COVERED BY A SLAB OF PAVING AT A TEMPERATURE TO PRECLUDE THE FORMATION OF ICE THEREON WHICH COMPRISES POSITIONING A PLURALITY OF CLOSED ELONGATED MEMBERS IN A HORIZONTALLY SPACED RELATIONSHIP, EACH HAVING A PORTION EXTENDING IN AN UPRIGHT DIRECTION BELOW SAID SURFACE WITH THE UPPER END ADJACENT TO AND SPACED BELOW, THE PAVING, POSITIONING SUBSTANTIALLY HORIZONTAL CONDENSATION CHAMBERS IN EMBEDDED RELATION IN THE PAVING IN A NETWORK, WITH THE CONDENSATION CHAMBERS EACH BEING ATTACHED TO ONE OF SAID UPRIGHT-EXTENDING PORTIONS TO COMPLETE THE CLOSED ELONGATED MEMBER, EACH OF SAID MEMBERS BEING PARTIALLY FILLED WITH A MEDIUM IN A LIQUID STATE AND CONVERTIBLE INTO A GASEOUS STATE UPON IMPOSITION OF HEAT IN THE RANGE OF AT LEAST SUBSTANTIALLY 45*F. THERETO AND CONVERTIBLE FROM THE GASEOUS STATE TO THE LIQUID STATE UPON IMPOSITION OF COLD IN THE RANGE OF AT LEAST SUBSTANTIALLY 32* F., THERETO, THE LOWER END PORTIONS OF SAID MEMBERS BEING SUBMERGED BELOW SAID SURFACE TO EXTENT SUCH AS TO LIE BELOW THE FROST LINE OF THE SUBTERRANEAN EARTH, THE LIQUID MEDIUM IN THE LOWER END PORTIONS OF SAID MEMBERS BEING SUBJECTED TO THE HEAT OF ADJACENT REGIONS OF THE SUBTERRANEAN EARTH TO THEREBY GASIFY SOME OF SAID MEDIUM AND CAUSE THE MEDIUM CONVERTED TO THE GASEOUS STATE TO BE EVOLVED FROM THE LIQUID MEDIUM AND FLOW INTO THE CONDENSATION CHAMBER OF SAID MEMBERS, THE MEDIUM IN THE GASEOUS STATE WHEN IN THE CONDENSATION CHAMBERS OF SAID MEMBEERS BEING SUBJECTED TO THE COLD OF THE ADJACENT PAVING TO THEREBY CONDENSE THE MEDIUM IN THE GASEOUS STATE AND BE RETURNED TO AND ABSORBED IN THE RESPECTIVE LIQUID MEDIUMS TO HEAT THE PAVING TO THE TEMPERATURE TO PRECLUDE FORMATION OF ICE. 